Hydrogenated copolymer, process for producing the same, and hot-melt adhesive composition containing the same

ABSTRACT

The present invention involves a hydrogenated copolymer obtained by hydrogenating a copolymer having a softening point falling in a range of 45 to 55° C. determined by a ball &amp; ring method, wherein the hydrogenated copolymer has a softening point of 85 to 95° C. determined by the ball &amp; ring method, and a hot melt adhesive composition comprising this copolymer hydrogenated product. The hydrogenated copolymer of the present invention has a small weight reduction rate in heating and a good hue after heating. The hot melt adhesive composition comprising the same has excellent fluidity in heating and has a small heating loss and a small change in a hue in heating and has excellent heat stability.

BACKGROUND OF THE INVENTION

The present invention relates to a hydrogenated copolymer, a productionprocess for the same and a hot melt adhesive composition using the same,more specifically to a hydrogenated copolymer which has a small weightreduction rate in heating and a good hue after heating and has anadhesion-providing property and which is suited as one component for ahot melt adhesive composition, a production process for the same and ahot melt adhesive composition which comprises the hydrogenated copolymerdescribed above and is excellent in a fluidity in heating and which hasa small heating loss and a small change in a hue in heating and has anexcellent heat stability and a good weatherability.

RELATED ART

In recent years, a hot melt adhesive has been expanding in a use thereofin various fields because it is excellent in a high speed coatingproperty, a rapid curing property, a barrier property, an energy savingproperty and an economical efficiency. Used as a conventional hot meltadhesive are, for example, compositions prepared by blendingadhesion-providing resins and plasticizers with base polymers such asnatural rubbers, ethylene-vinyl acetate copolymers,styrene-butadiene-styrene block copolymers and hydrogenated productsthereof, styrene-isoprene-styrene block copolymers and hydrogenatedproducts thereof. In general, Used as the adhesion-providing resindescribed above are petroleum resins, coumarone resins, phenol baseresins, terpene base resins, rosin base resins and hydrogenated productsthereof.

Such hot melt adhesive has to be applied after molten by heating inusing, and therefore products having a large heating loss are likely todamage health of an operator due to white smoke generated in melting byheating. Further, it brings about such unfavorable situations that anadverse effect is exerted on an adhesive performance of the finishedproduct or a fine appearance of the finished product is damaged by adeterioration in the hue after heating.

DISCLOSURE OF THE INVENTION

Under such circumstances, an object of the present invention is toprovide a hydrogenated copolymer which has a small weight reduction ratein heating and a good hue after heating and has an adhesion-providingproperty and which is suited as one component of a hot melt adhesivecomposition and a hot melt adhesive composition which comprises theabove hydrogenated copolymer and is excellent in a fluidity in heatingand which has a small heating loss and a small change in a hue inheating and has an excellent heat stability and a good weatherability.

Intensive researches repeated by the present inventors in order todevelop a hydrogenated copolymer and a hot melt adhesive compositioneach having the preferred properties described above have resulted infinding that the above object can be achieved by a hydrogenatedcopolymer which is obtained by hydrogenating a copolymer having asoftening point falling in a specific low range and in which a softeningpoint falls in a specific range. The present invention has beencompleted based on such knowledge.

That is, the present invention provides:

-   (1) a hydrogenated copolymer obtained by hydrogenating a copolymer    having a softening point falling in a range of 45 to 55° C.    determined by a ball & ring method, wherein the hydrogenated    copolymer has a softening point of 85 to 95° C. determined by the    ball & ring method,-   (2) the hydrogenated copolymer as described in the above item (1),    wherein the copolymer is obtained from cyclopentadiene and/or    dicyclopentadiene and a vinyl-substituted aromatic compound,-   (3) a production process for a hydrogenated copolymer having a    softening point of 85 to 95° C. determined by a ball & ring method,    characterized by subjecting a copolymer having a softening point    falling in a range of 45 to 55° C. determined by the ball & ring    method to hydrogenation treatment,-   (4) the production process for a hydrogenated copolymer as described    in the above item (3), wherein the copolymer is obtained from    cyclopentadiene and/or dicyclopentadiene and a vinyl-substituted    aromatic compound,-   (5) a hot melt adhesive composition comprising the hydrogenated    copolymer as described in the above item (1),-   (6) the hot melt adhesive composition as described in the above item    (5), wherein the copolymer is obtained from cyclopentadiene and/or    dicyclopentadiene and a vinyl-substituted aromatic compound, and-   (7) the hot melt adhesive composition as described in the above    item (5) or (6), further comprising a base polymer and a    plasticizer.

BEST MODE FOR CARRYING OUT THE INVENTION

In the hydrogenated copolymer of the present invention, a copolymerhaving a softening point falling in a range of 45 to 55° C. determinedby the ball & ring method is used as a copolymer before hydrogenation.In the present invention, a copolymer obtained from cyclopentadieneand/or dicyclopentadiene and a vinyl-substituted aromatic compound canbe used as this copolymer.

The softening point determined by the ball & ring method described aboveshows a softening point obtained by measuring based on JAI 7-1999.

In the copolymer described above, the vinyl-substituted aromaticcompound used as one component of the raw material monomers includes,for example, styrene, α-methylstyrene and vinyltoluene, and they may beused alone or in a combination of two of more kinds thereof.

The above copolymer is produced by copolymerizing cyclopentadiene and/ordicyclopentadiene and the vinyl-substituted aromatic compound describedabove which are the raw material monomers in a suitable solvent. In thiscase, capable of being preferably used as the solvent are, for example,hydrocarbon compounds such as benzene, toluene, xylene, cyclohexane,dimethylcyclohexane and ethylcyclohexane. They may be used alone or in acombination of two of more kinds thereof. A use amount of this solventis selected in a range of usually 50 to 500 mass parts, preferably 60 to300 mass parts per 100 mass parts of the monomers.

Advantageous as the polymerization method is a method in which thesolvent described above is heated preferably to 100° C. or higher, morepreferably 150° C. or higher to carry out copolymerization whiledivisionally adding a monomer mixture of cyclopentadiene and/ordicyclopentadiene and the vinyl-substituted aromatic compound to thisheated solvent.

A use proportion of cyclopentadiene and/or dicyclopentadiene and thevinyl-substituted aromatic compound shall not specifically be restrictedand falls in a range of usually 70:30 to 20:80, preferably 60:40 to40:60 on a mass basis. The divisionally adding time is usually 0.5 to 5hours, preferably 1 to 3 hours. The divisional addition is carried outpreferably in equal parts.

In this copolymerization reaction, the monomer mixture ofcyclopentadiene and/or dicyclopentadiene and the vinyl-substitutedaromatic compound is preferably reacted continuously as well afterfinishing divisionally adding them. In this case, the reactionconditions shall not specifically be restricted. The reactiontemperature is usually 200 to 350° C., preferably 250 to 300° C.; thereaction pressure is usually 0 to 2 MPa-G, preferably 0 to 1.5 MPa-G;and the reaction time is usually 0.5 to 8 hours, preferably 1 to 5hours.

After finishing the reaction, the reaction solution is subjected totreatment for removing volatile matters, for example, at a temperatureof 100 to 300° C. and a pressure of 0.1 to 10 kPa for 1 to 3 hours,whereby the intended copolymer is obtained.

In the copolymer thus obtained, the softening point determined by theball & ring method has to fall in a range of 45 to 55° C., and thevinyl-substituted aromatic compound unit has usually a content of 30 to90 mass %, a bromine value of 30 to 90 g/100 g and a number averagemolecular weight of 400 to 1,000. The average molecular weight describedabove is a value reduced to polystyrene measured by a gel permeationchromatography (GPC) (hereinafter, the same shall apply).

In the present invention, the copolymer thus obtained in which asoftening point (ball & ring method) falls in a range of 45 to 55° C. issubjected to hydrogenation treatment, whereby the hydrogenated copolymerof the present invention is produced.

In this hydrogenation reaction, catalysts of nickel, palladium, cobalt,platinum and rhodium bases are used as a catalyst. The copolymerdescribed above is hydrogenated on the conditions of a temperature of120 to 300° C., preferably 150 to 250° C., a reaction pressure of 1 to 6MPa·G and a reaction time of 1 to 7 hours, preferably 2 to 5 hours inthe presence of the catalyst described above in a suitable solvent, forexample, cyclohexane and tetrahydrofuran.

After finishing the reaction, the reaction solution is subjected totreatment for removing volatile matters, for example, at a temperatureof 100 to 300° C. and a pressure of 0.1 to 10 kPa for 1 to 3 hours,whereby the hydrogenated copolymer of the present invention is obtained.

In the hydrogenated copolymer of the present invention thus obtained,the softening point determined by the ball & ring method has to fall ina range of 85 to 95° C., and the vinyl-substituted aromatic compoundunit has usually a content of 0 to 35 mass %, a bromine value of 0 to 30g/100 g and a number average molecular weight of 400 to 1,000.

The hydrogenated copolymer of the present invention described above hasa small weight reduction rate and a good hue after heating and has anadhesion-providing property, and it is suited as one component of a hotmelt adhesive.

Next, the hot melt adhesive composition of the present inventioncomprises the hydrogenated copolymer of the present invention describedabove as an essential component and usually further comprises a basepolymer and a plasticizer in addition to the above hydrogenatedcopolymer.

The base polymer described above shall not specifically be restricted,and optional products can be selected from those used as a base polymerin a hot melt adhesive and used. The specific examples of this basepolymer include natural rubber, ethylene-vinyl acetate copolymers,amorphous poly-α-olefins, styrene-butadiene-styrene block copolymers(SBS), styrene-isoprene-styrene block copolymers (SIS), andstyrene-ethylene-butylene-styrene rubber (SEBS) andstyrene-ethylene-propylene-styrene rubber (SEPS) which are obtained byhydrogenating them. They may be used alone or in a combination of two ormore kinds thereof.

On the other hand, the plasticizer shall not specifically be restricted,and optional products can be selected from those used as a plasticizerin a hot melt adhesive and used. The specific examples of thisplasticizer include paraffin base process oils obtained by subjectingheavy oil fractions obtained by distilling crude oil at an atmosphericpressure to distillation at a reduced pressure and further refining itby hydrogenation reforming and dewaxing treatment, naphthene baseprocess oils obtained by subjecting it to extraction with a solvent,hydrogenation and clay treatment after distillation at a reducedpressure, polybutene and liquid poly-α-olefins. They may be used aloneor in a combination of two or more kinds thereof.

A content proportion of the respective components in the hot meltadhesive composition of the present invention is varied depending on therequired physical properties. Usually, the hydrogenated copolymer fallsin a range of 30 to 70 mass %; the base polymer falls in a range of 15to 40 mass %; and the plasticizer falls in a range of 10 to 40 mass %

An antioxidant, a wax and a filler in addition to the hydrogenatedcopolymer, the base polymer and the plasticizer each described above canbe added, if necessary, to the hot melt adhesive composition of thepresent invention as long as the required physical properties are notdamaged.

A method for preparing the hot melt adhesive composition of the presentinvention shall not specifically be restricted, and capable of beingused is, for example, a method in which the respective components areheated, molten and mixed or kneaded by means of a propeller typestirrer, a double shaft blender and a kneader. A blending order of therespective components shall not specifically be restricted. Further, theheating temperature shall not specifically be restricted as well, andheating, melting and mixing or kneading are carried out usually at atemperature of 120 to 190° C.

The hot melt adhesive composition of the present invention thus obtainedhas an excellent fluidity in heating, a small heating loss and heat huechange and an excellent heat stability and has a good weatherability,and it can be used in various fields such as, for example, sanitarymaterials, packaging, book-binding, non-woven materials, wood working,electric materials, can working, building, bag working and binders for aroad.

Next, the present invention shall be explained in further details withreference to examples, but the present invention shall by no means berestricted by these examples.

The physical properties of the copolymers and the hydrogenatedcopolymers and the performances of the hot melt adhesive compositionwere evaluated according to methods shown below.

<Physical Properties of the Copolymers and the Hydrogenated Copolymers>

(1) Softening Point

Measured by the ball & ring method according to JAI 7-1999.

(2) Styrene Unit Content

Determined by means of an infrared spectrophotometer (absorbance in awavelength of 700 cm⁻¹)

(3) Bromine Value

Measured according to JIS K 2605.

<Physical Properties of Hydrogenated Copolymers>

(4) Heating Loss

The hydrogenated copolymer 2 g was put on an aluminum-made Petri dishand heated at 180° C. for one hour to measure a heating loss, and theheating loss was determined according to the following equation:heating loss (%)=[(weight before heating−weight after heating)/(weightbefore heating)]×100(5) Heating Hue

The hydrogenated copolymer 20 g was put in a glass bottle and heated at180° C. for 48 hours, and it was then dissolved in toluene to determinea Gardner hue according to JIS K 6901.

<Performances of the Hot Melt Adhesive Composition>

(6) Heating Loss and Heating Hue

Measured in the same manners as in (4) and (5) described above.

(7) Softening Point

Measured according to JIS K 2207.

(8) Melt Viscosity

Measured according to JIS K 6862 by means of a B type viscometer.

(9) Adhesive Strength

Measured according to JIS Z 0237.

(10) Loop Tack

Measured according to a FINAT test standard.

(11) Holding Power

Measured according to JIS Z 0237.

PRODUCTION EXAMPLE 1

A one liter polymerization reactor equipped with a stirrer which wassubstituted with nitrogen was charged with 382 g of xylene and heated upto 260° C., and a mixture of 159 g of dicyclopentadiene and 159 g ofstyrene was added thereto in 120 minutes while stirring. Then, thecopolymerization reaction was continued for 110 minutes.

After finishing the reaction, the reaction solution was taken out andtreated at a temperature of 200° C. and a pressure of 1.3 kPa for 2hours by means of a rotary evaporator to remove the unreacted monomersand xylene to obtain 287 g of a copolymer of cyclopentadiene andstyrene. The physical properties of this copolymer are shown in Table 1.

PRODUCTION EXAMPLE 2

A copolymer was obtained in the same manner as in Production Example 1,except that in Production Example 1, the copolymerization reaction wascontinued for 130 minutes after the monomer mixture was added. Thephysical properties of this copolymer are shown in Table 1.

EXAMPLE 1

A 300 ml reactor equipped with a stirrer which was substituted withnitrogen was charged with 70 g of cyclohexane, 70 g of the copolymerobtained in Production Example 1 and 1.5 g of a nickel base catalyst tocarry out hydrogenation reaction at a hydrogen pressure of 4 MPa and atemperature of 230° C. for 4 hours.

After finishing the reaction, the reaction solution was taken out, and4,000 PPM of an antioxidant (brand name “Irganox 1010”, manufactured byCiba Specialty Chemicals Co., Ltd.) was added thereto. Then, thesolution was treated at a temperature of 200° C. and a pressure of 670Pa for 3 hours by means of a rotary evaporator to remove cyclohexane,whereby 70 g of a hydrogenated copolymer of cyclopentadiene and styrenewas obtained. The physical properties of this hydrogenated copolymer areshown in Table 1.

COMPARATIVE EXAMPLE 1

Hydrogenation reaction was carried out in the same manner as in Example1, except that in Example 1, the copolymer obtained in ProductionExample 2 was substituted for the copolymer obtained in ProductionExample 1.

After finishing the reaction, the reaction solution was taken out, and4,000 PPM of the antioxidant (brand name “Irganox 1010”, manufactured byCiba Specialty Chemicals Co., Ltd.) was added thereto. Then, thesolution was treated at a temperature of 200° C. and a pressure of 1.3kPa for one hour by means of a rotary evaporator to remove cyclohexane,whereby 70 g of a hydrogenated copolymer of cyclopentadiene and styrenewas obtained. The physical properties of this hydrogenated copolymer areshown in Table 1. TABLE 1 Production Example Comparative 1 2 Example 1Example 1 Softening point (° C.) 50 60 91 90 Styrene unit content (mass%) 48 47 2 2 Bromine value (g/100 g) 55 55 3 3 Heating hue (Gardner) — —4 7 Heating loss (mass %) — — 6.3 9.6

As shown in Table 1, while the copolymer obtained in Production Example1 had a softening point of 50° C., the hydrogenated copolymer obtainedin Example 1 had a softening point of 91° C. Further, the hydrogenatedproduct obtained in Example 1 had a heating loss of 6.3 mass % whenheated at 180° C. for one hour and a Gardner hue of 4 when heated at180° C. for 48 hours.

In contrast with this, the copolymer obtained in Production Example 2had a softening point of 60° C., and the hydrogenated copolymer obtainedin Comparative Example 1 had a softening point of 90° C. Further, thehydrogenated product obtained in Comparative Example 1 had a heatingloss of 9.6 mass % when heated at 180° C. for one hour and a Gardner hueof 7 when heated at 180° C. for 48 hours.

As shown above, the hydrogenated copolymer obtained in Example 1 had asmaller heating loss and a better hue after heating than those of thehydrogenated copolymer obtained in Comparative Example 1.

EXAMPLE 2

Used in a proportion shown in Table 2 were the hydrogenated copolymerobtained in Example 1, an SEBS copolymer (brand name “Craton G1652”,manufactured by Shell Japan Co., Ltd.; styrene component/rubbercomponent mass ratio=29/71), an oil (brand name “PS-32”, manufactured byIdemitsu Kosan Co., Ltd.) and an antioxidant (brand name “Irganox 1010”,manufactured by Ciba Specialty Chemicals Co., Ltd.). They were blendedat 140° C. for 40 minutes by means of a kneading machine Lab Plast Millto prepare a hot melt adhesive composition and evaluate the performancesthereof. The results thereof are shown in Table 2.

COMPARATIVE EXAMPLE 2

A hot melt adhesive composition was prepared in the same manner as inExample 2, except that in Example 2, the hydrogenated product obtainedin Comparative Example 1 was substituted for the hydrogenated productobtained in Example 1 to evaluate the performances thereof. The resultsthereof are shown in Table 2. TABLE 2 Comparative Example 2 Example 2Blend ratio SEBS (Craton G1652) 20 20 (mass part) Hydrogenated copolymerof 60 — Example 1 Hydrogenated copolymer of — 60 Comparative Example 1Oil (PS-32) 20 20 Antioxidant (Irganox 1010) 1 1 Performance Softeningpoint (° C.) 82 82 Melt viscosity [160° C.] (mPa.s) 2400 2480 Adhesivestrength [23° C.] 8.5 8.6 (N/cm) Loop tack [23° C.] (N/cm) 5.4 5.3Holding power [50° C.] (mm/h) 0.8 0.7 Heating hue [Gardner] 6 8 Heatingloss (mass %) 2.1 3.6

According to Table 2, the hot melt adhesive composition prepared inExample 2 was almost equal to the hot melt adhesive composition preparedin Comparative Example 2 in terms of an adhesive strength, a loop tackand a holding power but improved in a loss and a hue in heating.

INDUSTRIAL APPLICABILITY

According to the present invention, capable of being provided is ahydrogenated copolymer which has a small weight reduction rate inheating and a good hue after heating and which has an adhesion-providingproperty and is suited as one component of a hot melt adhesivecomposition.

Further, the hot melt adhesive composition of the present inventioncomprising the hydrogenated copolymer described above is excellent in afluidity in heating and has a small heating loss and a small change in ahue in heating, and it is excellent in a heat stability and has a goodweatherability.

1. A consumable authentication protocol for validating the authenticityof an untrusted authentication chip contained within a consumable, theprotocol includes the steps of: generating an original random number ina trusted authentication chip; applying, in a trusted authenticationchip contained within a consuming device an asymmetric encrypt functionto the original random number using a first key from the trustedauthentication chip to produce a first encrypted outcome; passing thefirst encrypted outcome to the untrusted authentication chip;decrypting, in the untrusted authentication chip, the first encryptedoutcome with an asymmetric decrypt function using a second secret keyfrom the untrusted authentication chip to produce a first decryptedoutcome; applying, in the untrusted authentication chip, an asymmetricencrypt function to the first decrypted outcome together with anoriginal data message read from the untrusted authentication chip usingthe second secret key to produce a second encrypted outcome; passing thesecond encrypted outcome together with the original data message to thetrusted authentication chip; decrypting, in the trusted authenticationchip, the second encrypted outcome with an asymmetric decrypt functionusing the first key to produce a decrypted random number and a decrypteddata message; comparing the decrypted random number and the decrypteddata message with the original random number and the received originaldata message, without knowledge of the second secret key; and, in theevent of a match, considering the untrusted chip and the data message tobe valid, otherwise considering the untrusted chip and the data messageto be invalid.
 2. A consumable authentication protocol according toclaim 1, for validating the authenticity of an untrusted authenticationchip, as well as ensuring that the authentication chip, lasts only aslong as the consumable including the further steps of writing new datato the untrusted chip, performing the steps of claim 1, and in the eventthe untrusted chip is found to be authentic and the new data is the sameas the data message read from the untrusted chip, then the write isvalidated.
 3. A consumable authentication protocol according to claim 1,where the first key is a public key.
 4. A consumable authenticationprotocol according to claim 1, where encryption outside the untrustedchip is implemented in software.
 5. A consumable authentication protocolaccording to claim 4, where the random number generation, encryption,passing, and final decrypting and comparing steps take place in anexternal system.
 6. A consumable authentication protocol according toclaim 5, where the external system is in a printer or other device inwhich consumables such as ink cartridges are mounted.
 7. (canceled)
 8. Aconsumable authentication protocol according to claim 1, where theencryption outside the untrusted chip is implemented in a secondauthentication chip, and an external system intermediates between thetwo chips.
 9. A consumable authentication protocol according to claim 8,where the second authentication chip and system are in a printer orother device in which consumables are mounted.
 10. (canceled)
 11. Aconsumable authentication protocol according to claim 1, where thesecret key is held only by the untrusted chip.
 12. A consumableauthentication protocol according to claim 1, where the trustedauthentication chip contains a random function to produce random numbersfrom a seed, and the function advances after every successfulauthentication so that the next random number will be produced from adifferent seed
 13. A consumable authentication protocol according toclaim 1, where the data message is a memory vector of the authenticationchip, a part is different for each chip, and parts of it are constant(read only) for each consumable, or decrement only so that it can becompletely downcounted only once for each consumable.
 14. A consumableauthentication system for validating the authenticity of an untrustedauthentication chip, where the system comprises: a consuming devicecontaining a trusted authentication chip; a random number generator togenerate an original random number in the trusted authentication chip;an asymmetric encryptor to encrypt the generated original random numberwith an asymmetric encryption function to produce a first encryptedoutcome using a first key for the encryptor; a consumable containing theuntrusted authentication chip which a read function which operates todecrypt the first encrypted outcome using a second secret key andproduce a second first decrypted outcome, then applies the symmetricencrypt function to the first decrypted outcome together with anoriginal data message read using the second secret key to produce asecond encrypted outcome, also returning the second encrypted outcometogether with the original data message; and, a test function, the testfunction operating to decrypt the second encrypted outcome using thefirst key to produce a decrypted random number and a decrypted datamessage, and compare the decrypted random number and decrypted datamessage with the generated original random number and the receivedoriginal data message, without knowledge of the second secret key;whereby, in the event of a match the test function returns a valueindicating validity, otherwise the test function returns a valueindicating invalidity.
 15. A consumable authentication system accordingto claim 14, where new data written to the untrusted chip is consideredvalid in the event the untrusted chip is found to be authentic and thenew data is the same as the data message read from the untrusted chip.16. A consumable authentication system according to claim 14, where thefirst key is a public key.
 17. A consumable authentication systemaccording to claim 14, where encryption outside the untrusted chip isimplemented in software.
 18. A consumable authentication systemaccording to claim 17, where the random number generation, encryption,passing, and final decrypting and comparing steps take place in anexternal system.
 19. A consumable authentication system according toclaim 18, where the external system is in a printer or other device inwhich consumables such as ink cartridges are mounted.
 20. (canceled) 21.A consumable authentication system according to claim 14, where theencryption outside the untrusted chip is implemented in a secondauthentication chip, and an external system intermediates between thetwo chips.
 22. A consumable authentication system according to claim 21,where the second authentication chip and system are in a printer orother device in which consumables are mounted.
 23. (canceled)
 24. Aconsumable authentication system according to claim 14, where the secretkey is held only by the untrusted chip.
 25. A consumable authenticationsystem according to claim 14, where the random number generator of thetrusted authentication chip contains a random function to produce randomnumbers from a seed, and the function advances after every successfulauthentication so that the next random number will be produced from anew seed.
 26. A consumable authentication system according to claim 25where for a group of authentication chips, the initial seed for eachchip is different from that of the others in the group so that the firstrandom number produced by each chip in the group will be different. 27.A consumable authentication system according to claim 14, where the datamessage is a memory vector of the authentication chip, a part isdifferent for each chip, and parts of it are constant (read only) foreach consumable, or decrement only so that it can be completelydowncounted only once for each consumable.